| 摘要 |
<p>A phase demodulator is disclosed which is capable of ensuring orthogonality at all times thereby eliminating deterioration in bit error rate due to changes in the circuit constant of a phase shifter. The phase demodulator has a first phase detector for phase-detecting an input digitalsignal-modulated carrier wave with a reference carrier wave fed thereto and a variable phase shifter for controlling the phase of the reference carrier wave in response to a control signal. Also included in the demodulator is a second phase detector for phase-detecting the input digital-signal-modulated carrier wave in response to an output of the variable phase shifter supplied thereto. A multi-level discriminator is included for multi-level-discriminat-ing the outputs of the first and second phase detectors, and logic circuitry is included for logically processing the output of the discriminator and providing an orthogonality error signal as the control signal.</p> |
